A102617 - OEIS

A102617

Primes prime(k) where k is a second-order nonprime number.

2, 19, 29, 43, 47, 53, 71, 79, 89, 97, 103, 113, 131, 137, 149, 151, 163, 167, 173, 193, 199, 223, 227, 229, 233, 251, 257, 263, 271, 293, 307, 311, 317, 337, 347, 349, 359, 379, 383, 389, 397, 409, 421, 439, 443, 449, 457, 463, 479, 487, 491, 503, 523, 541

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OFFSET

1,1

COMMENTS

The prime/nonprime compound sequence ABB. - N. J. A. Sloane, Apr 06 2016

LINKS

Table of n, a(n) for n=1..54.

EXAMPLE

Nonprime(4) = 8. The 8th prime is 19, the second entry.

MAPLE

# For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016

MATHEMATICA

nonPrime[n_Integer] := FixedPoint[n + PrimePi[ # ] &, n]; Prime /@ nonPrime /@ nonPrime /@ Range[54] (* Robert G. Wilson v, Feb 04 2005 *)

PROG

(PARI) /* We perform nesting(s) with a loop. */ cips(n, m) = { local(x, y, z); for(x=1, n, z=x; for(y=1, m+1, z=composite(z); ); print1(prime(z)", ") ) }

composite(n) = /* The n-th composite number. 1 is defined as a composite number. */ { local(c, x); c=1; x=0; while(c <= n, x++; if(!isprime(x), c++); ); return(x) }

CROSSREFS

Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270796, A102216.

Sequence in context: A083689 A390136 A384997 * A365235 A290163 A284496

Adjacent sequences: A102614 A102615 A102616 * A102618 A102619 A102620

KEYWORD

nonn

AUTHOR

Cino Hilliard, Jan 31 2005

EXTENSIONS

Edited by Robert G. Wilson v, Feb 04 2005

STATUS

approved